U.S. patent number 6,155,988 [Application Number 09/272,163] was granted by the patent office on 2000-12-05 for device for taking samples, for example for a biopsy, and rack system fitted to such a device.
This patent grant is currently assigned to Nivarox-FAR S.A.. Invention is credited to Jean-Bernard Peters.
United States Patent |
6,155,988 |
Peters |
December 5, 2000 |
Device for taking samples, for example for a biopsy, and rack
system fitted to such a device
Abstract
The present invention concerns a device for taking samples, for
example for biopsies, of the type including a mechanical control
system (2) sliding inside a flexible sheath (4) and connecting a
control handle to a clamp (6) formed of pivoting jaws (8),
characterised in that the control system (2) includes a cylindrical
rack (28), and in that the jaws (8) of the clamp (6) each have, on
a circular portion of their perimeter, a toothing (34) engaging the
cylindrical rack (28) for the opening and closing of said jaws
(8).
Inventors: |
Peters; Jean-Bernard (La
Chaux-de-Fonds, CH) |
Assignee: |
Nivarox-FAR S.A. (Le Locle,
CH)
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Family
ID: |
8231646 |
Appl.
No.: |
09/272,163 |
Filed: |
March 19, 1999 |
Foreign Application Priority Data
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Mar 26, 1998 [EP] |
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98105473 |
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Current U.S.
Class: |
600/564 |
Current CPC
Class: |
A61B
10/06 (20130101); A61B 2017/2933 (20130101); A61B
2017/2943 (20130101) |
Current International
Class: |
A61B
10/00 (20060101); A61B 17/28 (20060101); A61B
005/00 () |
Field of
Search: |
;600/562,564
;606/170,174,205-208 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 573 817 A1 |
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May 1993 |
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EP |
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29 45 237 A1 |
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May 1981 |
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DE |
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Primary Examiner: Hindenburg; Max
Attorney, Agent or Firm: Pollock, Vande Sande &
Amernick
Claims
What is claimed is:
1. A device for taking samples, for example for biopsies, said
device comprising a mechanical control system sliding inside a
flexible sheath and connecting a control handle to a clamp formed
of at least two pivoting jaws, wherein the control system includes
a cylindrical rack having an annular tooth formed by an annular
groove, and wherein the jaws of the clamp each have, on a circular
portion of their perimeter, a toothing for engaging said annular
tooth of the cylindrical rack for the opening and closing of said
jaws.
2. A device for taking samples according to claim 1, wherein the
toothing engages the cylindrical rack by at least two of its
teeth.
3. A device for taking samples according to claim 1, wherein the
apparent number of teeth distributed on the primitive diameter of
the toothing is at most six.
4. A device for taking samples according to claim 1, wherein the
cylindrical rack is formed by an alternating succession of annular
teeth and annular grooves.
5. A device for taking samples according to claim 4, wherein the
line formed by the points of contact between the teeth of the rack
and the teeth of the toothing is longer after the neutral line than
before said neutral line.
6. A device for taking samples according to claim 1, wherein the
toothings of the jaws each have a stop which blocks the axial
sliding of the cylindrical rack in an end of travel position.
7. A device for taking samples according to claim 1, further
comprising a fork having a diametral groove in which a mounting
portion of the jaws are housed.
8. A device for taking samples according to claim 1, wherein a
needle is provided at the end of the cylindrical rack.
9. A device according to claim 1, wherein said cylindrical rack
forms a driver pinion and said toothing forms a driven pinion to
provide a gearing system.
10. A device according to claim 9, wherein the toothing engages the
cylindrical rack by at least two of its teeth.
11. A device according to claim 9, wherein the apparent number of
teeth distributed on the primitive diameter of the toothing is at
most six.
12. A device according to claim 9, wherein the cylindrical rack is
formed by an alternating succession of annular teeth and annular
grooves.
13. A device according to claim 12, wherein the line formed by the
points of contact between the teeth of the rack and the teeth of
the toothing is longer after the neutral line than before said
neutral line.
14. A device according to claim 9, wherein the toothings each have
a stop which blocks the axial sliding of the cylindrical rack in an
end of travel position.
Description
The present invention concerns a device for taking samples, for
example for biopsies, of the type including a control cable sliding
inside a flexible sheath, and a clamp formed of at least two
pivoting jaws or grips. The invention also concerns a transmission
rack system with improved mechanical couple between a driver pinion
and a driven pinion.
Biopsy clamps are in particular used for taking tissue samples from
the live organs of a patient, for example for the purposes of
clinical tests. These clamps conventionally include cutting jaws
actuated from a distance by a manipulator by means of a control
device including a handle connected to the jaws by a cable system
sliding inside a flexible sheath. The clamp and the flexible sheath
are introduced into the tub of an endoscope via which the clamp is
led to the desired location where the sample is to be taken.
This equipment is used by qualified personnel who, although warned
of the fragility of these instruments, cannot avoid very frequent
breakage of the cables which assure the opening and closing of the
jaws of said instruments. It should be noted that these clamps,
because of their destination and the manner in which they are used,
are of very small dimensions and their cables are extremely thin.
It should also be noted that the pressure which has to be exerted
on the handle to assure the closing movement of the jaws must be
strong enough to be able to remove fragments of tissue or mucous by
cutting. This pressure cannot however be accurately measured and
monitored, so that it is left to the person manipulating the device
to evaluate the pressure which he does not always do correctly,
which is the cause of cable breakage.
Various solutions have been proposed to attempt to overcome these
problems and assure more accurate and efficient sample taking.
By way of example, U.S. Pat. No. 5,582,617 can be cited, which
proposes a biopsy clamp of the type including two jaws articulated
so as to pivot around a common axis, these jaws each having a
circular toothed profile engaging a rectilinear rack crimp
connected onto the control cable of the clamp. By traction on the
cable, the clamp jaws close again.
Another embodiment of a clamp is known from U.S. Pat. No.
5,209,747. This clamp includes a control stem having two
rectilinear racks which each engage the circular toothed profile of
one of the jaws of the clamp.
These known solutions have several drawbacks. It will be noted
first that the mechanical couple is transmitted to the jaws or
driven pinions of the clamps by a single tooth of the rectilinear
racks or driver pinions. The pressure exerted on the handle by the
person manipulating the device is thus only partially transmitted
to the jaws of the clamp, so that there is a significant risk of
tearing and ripping the tissues to be taken. The fact that such
clamps cannot include more than two jaws and that the volume of
samples which they can take is therefore limited, should also be
considered. Finally, such clamps are generally unreliable. In the
event of breakage of the control cable or the crimp connection
coming undone, there is a risk of the racks escaping and falling
into the patient's body.
A biopsy clamp including a transmission cable sliding inside a
flexible sheath and connecting a control handle to a clamp formed
of two pivoting jaws is also known from U.S. Pat. No. 5,275,615.
According to the biopsy clamp described in this document, the clamp
includes a cylindrical control stem having two semi-circular racks
which each engage the circular toothed profile of one of jaws of
the clamp. Such a clamp cannot therefore include more than two
jaws, which limits its sample taking volume. It will also be noted
that the gearing used in this Patent is a standardized gearing with
at least twelve apparent teeth distributed on the primitive
diameter of the circular toothed profile of each of the jaws of the
clamp. The drawbacks of standardized toothings are well known in
the field of micro-mechanics: poor gearing guiding, fragile teeth,
poor transmission of the mechanical couple exerted by the operator
when he actuates the control handle.
The object of the present invention is to overcome the above
problems and drawbacks by providing a device for taking samples, in
particular for biopsies, which operates reliably and allows good
transmission of the pressure exerted by the operator on the control
handle to the clamp.
The invention therefore concerns a device for taking samples for
example for biopsies, of the type including a mechanical control
system sliding inside a flexible sheath and connecting a control
handle to a clamp formed of pivoting jaws, characterised in that
the control system includes a cylindrical rack, and in that the
jaws of the clamp each have, on a circular portion of their
perimeter, a toothing engaging the cylindrical rack for the opening
and closing of said jaws.
Since the rack according to the invention has a general revolution
symmetry, the number of jaws of the clamp can be increased and
brought to at least three. It is thus possible to increase the
sample volume of the clamp, and to improve the efficiency and
accuracy of the sample taking.
According to another feature of the invention, the toothings of the
jaws of the clamp engage the cylindrical rack with at least two of
the teeth thereof. The mechanical couple corresponding to the
pressure exerted by the operator on the control handle of the
sample taking device according to the invention is thus transmitted
in its entirety to the jaws of the clamp, which assure accurate and
efficient sample taking, without risking tearing or ripping for
example the tissues to be taken.
According to another feature of the invention, the toothings of the
jaws of the clamp each have a stop which blocks the axial sliding
of the cylindrical rack in an end of travel position. As a result
of this other advantageous arrangement, the cylindrical rack cannot
be lost even in the event of breakage of the control cable or
release of the crimp connection or the welding, which provides a
high level of security of use for the sample taking device
according to the invention.
According to a further feature of the invention, the apparent
number of teeth distributed on the primitive diameter of the
gearing is at most six. Thus, by dividing the apparent number of
teeth by two with respect to a standardized gearing, the present
invention allows a gearing with more solid teeth, better guiding
and better transmission of the mechanical couple exerted by the
operator when he actuates the control handle, to be obtained.
The present invention also concerns a rack system including a
driver pinion and a driven pinion, characterised in that the driver
pinion is a cylindrical rack, and in that the driven pinion has, on
a circular portion of the perimeter thereof, a toothing engaging
the cylindrical rack.
Other features and advantages of the present invention will appear
more clearly upon reading the following detailed description of an
embodiment example of the sample taking device according to the
invention, this example being given purely by way of illustrative
and non limiting example, in conjunction with the annexed drawings,
in which:
FIG. 1 is a general perspective view of the sampling clamp
according to the invention in a fully open position with the fork
partially torn away;
FIG. 2 is a longitudinal cross-section of the sampling clamp of
FIG. 1 in a fully open position;
FIG. 3 is a longitudinal cross-section of the sampling clamp in a
closed position;
FIG. 4 is a detailed view of the portion surrounded with a dot and
dash line in FIG. 3;
FIG. 5 is a cross-section along the line V--V of FIG. 3, the jaws
of the clamp having been removed, and
FIG. 6 is a partial view of the gearing system according to the
invention.
The sample taking device according to the invention will be
described in the medical application thereof to the taking of
tissue samples from live organs or biopsies. Nonetheless, it goes
without saying that this device can be used for other purposes for
gripping or taking samples, fragments or particles of various
natures, organic, mineral or other.
As FIG. 1 clearly shows, the sample taking device according to the
invention, designated as a whole by the general numerical reference
1, includes a mechanical control system formed by a transmission
cable 2 sliding axially inside a flexible sheath 4 and connecting a
control handle (not shown) to a clamp 6 formed of two pivoting jaws
8. By traction on cable 2, jaws 8 of clamp 6 close.
Within the application of the present invention to forming biopsy
clamps or other clamps intended to take samples of fragments of
material, jaws 8 can have, on the inner face thereof, a
substantially hemispherical cavity 10 having a cutting edge 12
towards its upper edge. Thus, when clamp 6 is closed, jaws 8
delimit a sufficiently significant sampling volume to encompass a
fragment of biological tissue, a mineral or other fragment. Jaws 8
can be made entirely of stainless steel or of a suitable
biocompatible plastic material, cutting edges 12 being then added
onto jaws 8 in the form of metal inserts. It goes without saying
that a significant range Of jaws 8 of different shapes can be
proposed to users as a function of their requirements.
Jaws 8 of clamp 6 each include a mounting branch 14 whose end has a
hole 16 for the passage of a shaft 18. As FIG. 2 clearly shows,
jaws 8 are mounted so as to pivot around shafts 18 on a fork 20
fixed to the distal end of flexible sheath 4 by crimp connection,
welding or any other suitable technique. This fork 20, for example
of generally cylindrical outer shape, has a diametrical groove 22
in which mounting branches 14 of jaws 8 are housed.
Jaws 8 of clamp 6 are thus completely protected and there is no
risk of them being damaged during cleaning, conventionally by
brushing, of said clamp 6.
According to the present invention, fork 20 also includes at the
centre thereof a longitudinal channel 24 for guiding the axial
sliding of a control stem 26 fixed by crimp connection, welding or
other means to the free end of transmission cable 2. According to a
first advantageous feature of the invention, control stem 26 has at
the top thereof a cylindrical rack or driver pinion 28 formed by an
alternating succession of annular teeth 30 and annular grooves 32.
Teeth 30 which have the shape of full discs can advantageously be
formed integral with control stem 26, for example by
profile-turning. Cylindrical rack 28 shown in the Figures only
includes two teeth 30. However, it goes without saying that as a
function of the required destination and manner in which clamp 6 is
to be used, this number can be increased.
Mounting branches 14 of jaws 8 each have on a circular portion of
the perimeter thereof, a toothing or driven pinion 34 whose teeth
36 engage cylindrical rack 28 so that, by traction on transmission
cable 2, jaws 8 of clamp 6 close.
As FIG. 4 clearly shows, toothings or driven pinions 34 engage
cylindrical rack or driver pinion 28 with two of their teeth 36. As
a result of this feature, the mechanical couple corresponding to
the pressure exerted by the operator on the control handle of the
sample taking device according to the invention is transmitted in
its entirety to jaws 8 of clamp 6, which assures accurate and
efficient sample taking, without risking tearing or ripping the
tissues to be taken. It should also be noted that the substantially
revolution geometry of cylindrical rack 28 allows one to envisage
increasing the number of jaws 8 which form clamp 6, bringing the
number for example to three. It is thus possible to increase the
sampling volume of clamp 6 and to further increase the accuracy and
efficiency of the sample taking.
The gearing system described hereinbefore is a system of special
type having teeth of very high resistance. As FIG. 6 shows, the
apparent number of teeth 36 of the driven pinion 34 of this system
is at most six, distributed on the primitive diameter 38 of said
driven pinion 34. According to an advantageous feature of the
invention, the line 40 formed by the points of contact between the
teeth 30 of the driver pinion 28 and the teeth 36 of the driven
pinion 34 is longer after the neutral line 42 (output of the
gearing) than before the neutral line 42 (input of the gearing).
Neutral line 42 means herein the straight line that passes by the
center of the pinion 34 and which is perpendicular to the straight
line 44 tangential to the primitive diameter 38 of said pinion 34.
This arrangement makes it possible to avoid any blockage point
typical of standardized gearings with a small number of teeth for
which the line of contact points is symetrical with respect to the
neutral line. This creates a phenomenon of friction at the input of
the gearing system.
According to another advantage of the invention, toothings 34 of
jaws 8 each have an end of travel stop 46 which prevents axial
sliding of cylindrical rack 28 in the fully open position of clamp
6. Rack 28 cannot therefore be lost, even in the event of breakage
of transmission cable 2, or release of the weld or crimp connection
by which control stem 26 is fixed to said transmission cable 2. The
risk of seeing control stem 26 fall for example into a patient's
organism is thus removed, which gives the present device a high
level of security of use. It should also be noted that in the event
of breakage of transmission cable 2, the closing of jaws 8 of clamp
6 nonetheless remains possible by simply pulling said clamp 6 back
inside the endoscope tube, without risking damaging the latter.
A needle can also be provided at the end of cylindrical rack 28, so
as to be able to place clamp 6 in a precise location prior to
taking a sample by closing jaws 8.
It goes without saying that in addition to the means described,
various simple modifications and variants fall within the scope of
the present invention.
* * * * *